The LTE (Long Term Evolution) network is evolution of GPRS or universal mobile telecommunications system (UMTS) standard to provide very high speed packet switched data services. Packet-switched data services are used for transmitting chunks of data or for data transfers of an intermittent or bursty nature. Typical applications for 3GPP packet service include Internet browsing, wireless e-mail, audio/video media applications and credit card processing, etc. As the adoption of mobile broadband increases, the need for a higher capacity backhaul goes up. Evolved high speed packet access (HSPA+) already provides a bandwidth in tens of Mbps per user and adding Femto services to the third-generation (3G) offerings will provide users access to more and more broadband data services. LTE will provide very high speed data access—such as 25-100 Mbps per UE.
FIG. 1 is a block diagram illustrating a typical LTE network architecture. Referring to FIG. 1, user equipments (UEs) 101-103 are communicatively coupled to a LTE core network 110 via a respective access network or cell. For example, UE 101 is coupled to the core network 110 via eNodeB (eNB) 104 such as an IP-BTS access network. UE 102 is coupled to the core network 110 via eNB 105 such as a Femtocell (e.g., home eNode B or HeNB). UE 103 is coupled to the core network 110 via eNB 106 such as a long term evolution (LTE) access network (e.g., evolved UMTS terrestrial RAN (E-UTRAN) node B or eNB).
eNodeB (evolved NodeB) is a term used in LTE (Long Term Evolution—aka 4G) similar to NodeB in UMTS (Universal Mobile Telecommunications System) equivalent to the BTS (base transceiver station) description used in GSM. It is the hardware that is connected to the mobile phone network that communicates directly with mobile handsets. In contrast with UMTS base stations, eNodeB uses OFDMA as the air interface technology. As in all cellular systems, such as UMTS and GSM, the eNodeB contains radio frequency transmitter(s) and the receiver(s) used to communicate directly with mobile devices, which move freely around it. In this type of cellular network, the mobile devices cannot communicate directly with each other but have to communicate with the eNodeB. Each eNodeB serves one or more E-UTRAN cells. eNodeBs can be interconnected with each other by means of X2 interface. A home eNB (HeNB) connects to an existing residential broadband service. An HeNB provides LTE radio coverage for LTE handsets within a home.
In order to access other networks such as Internet and/or operator services node, UEs 101-103 have to go through core network 110. Typically, LTE core network 110 includes a serving gateway (S-GW) 107 and a gateway packet data network (PDN) P-GW 108. These S-GW and P-GW relay communications between a user terminal (e.g., source mobile station) and a destination. Note that typically, there may be multiple S-GWs associated with a P-GW, multiple access networks associated with an S-GW, and multiple UEs associated with an access network in a hierarchical structure (not shown).
Typically, each of eNBs 104-106 communicates with core network 110 via S1 links 111-113, respectively. Each of eNBs 104-106 communicates with rest of the eNBs 104-106 via a specific X2 interface such as X2 links 114-116, respectively. Thus, for every two eNBs there is an X2 link, which forms a full mesh amongst eNBs in a particular domain. Note that although only three eNBs are shown for the purpose of illustration, more eNBs may exist, which exponentially increases density of the mesh amongst the eNBs. Depending on the deployment scenario, the X2 interface traffic between two eNBs can be secured or unsecured. If an eNB needs to send secured X2 traffic to the rest of the eNBs, that eNB has to maintain many secure connections with each of the rest of eNBs, or vice versa (e.g., a full mesh). As more and more eNBs (or HeNB) are involved, such a configuration becomes complicated and difficult to manage and very costly.